Transposing device for keyed instruments



April 10, 192-8. 1,666,025

J. ZUMBUHL TRANSPOSING DEVICE FOR KEYED INSTRUMENTS Filed. Feb, 26v1925- 2 Sheets-Sheet 1 [rm anion- 'J "ZWNMA/ April 10, 1928. 1,666.025

J. ZUMBUHL TRANSPOSING DEVICE FOR KEYED INSTRUMENTS Filed. Feb. 26. 19252 Sheets-Sheet 2 Fig.5.

Patented Apr. 10, 1928.

UNITED STATES PATENT OFFICE.

JULES ZUMBIIHL, F BASED, SWITZERLAND.

TRAN SPOSIN G DEVICE FOR KEYED INSTRUMENTS.

Application filed February 26, 1925, Serial No. 11,769, and in GermanyMarch 10, 1924.

This invention relates to transposin devices for keyed musicalinstruments, 0 the kind in which the wrest-plank or stringplate iscapable of being shifted sideways by means of a device through a certainnumber of semitones, so as to enable the same members of the keymechanism to play in a higher or lower key.

With cross-stringed instruments this arrangement has shown the need ofimprovement in view of the interposition of the hammer action betweenthe keyboard and the string-plate, in order to allow the movement to thedesired pitch to be effected correctly and safely. For this purposeaccording to the present invention the hammer action is so connectedwith the string-plate, that it can be shifted together with the samerelatively to the keys, so that it always participates, therefore, inthe movements of the string-plate. In this way the hammer action alwayskeeps the same position with relation to the stringing ofthestring-plate. Only through this invention a cross stringed piano becomestransposable by shifting the stringbox base or string-plate, the newfeature consisting in the simultaneous displacement of the hammeraction.

The accompanying drawing illustrates by way of example an embodiment ofthis improvement.

Figure 1 is a front view and Figure 2 a cross section thereof.

Figure 3 shows on an enlarged scale a cross section of the playingmechanism.

The string-plate a with the diagrammatically indicated stringing b issupported above and below by roller guides so as to be able to movesideways. Its movement is effected by means of a short toothed rack cand a pinion d which can be rotated from in front. It is held in itspositions by a spring pressed bolt 6 which engages notches in thetoothed rack c.

On the string-plate a by means of the frame f is fastened the hammeraction of known type indicated generally by 9, so that it participatesin the sideways movement of the string-plate.

The hammer action 9 is operated through the medium of transmission barsh (Figure 3) connected to the usual rocking levers m and guided by shortlinks n carried by a supporting beam 0 mounted on the frame Thetransmission bars IL project below out of the frame 7 and terminate attheir lower end in a socket z' for a tappet ball 1". The bars it arearranged side by side as well as their ball sockets 2' which in this wayconstitute an uninterrupted series of tappet pieces placed above therear ends of the key levers is. When a key lever is is actuated, itsrear end raises the corresponding transmission bar it which, through itsrocking lever m, operates the corresponding hammer device. As there isno positive connection between the key levers k and the correspond ingtransmission bars h, the frame f together with the hammer action and theactuating bars k can easily be displaced sideways with the movablestring-plate without being hindered by the key levers. Indeed, when theframe 7' is displaced sideways, the balls '1' at the lower end of thebars 71 ride or roll freely over the rear ends of the key levers k,which thus in their normal position do not interferewith saiddisplacement, as will be easily understood from Figures 1 and 3.

What I claim is:

In a keyed musical instrument a board of keys, a movable string-plate,an intermediate hammer action and means for connecting the hammer actionto the string-plate so that it is movable therewith relatively to thekeys.

In Witness whereof I have hereunto signed my name this 14th day ofFebruary, 1925.

J ULES ZUMBIIHL.

